1. Field of the Invention
The present invention is directed toward a method and apparatus for an implant anchor for a dental prosthesis and, more particularly, a one-piece threaded implant anchor with an upper receptacle, for insertion into an oral cavity, into which an angled or straight prosthesis support is secured, for removable attachment of a dental prosthesis.
2. Related Art
Various methods and structures for anchoring appliances in the oral cavity are known in the art. For example, U.S. Pat. No. 4,540,367, issued to Sulc, (xe2x80x9cthe ""367 Sulc patentxe2x80x9d) describes a multi-piece apparatus having a female member which attaches to a surface of a tooth adjacent to an apparatus anchoring site. Also shown in the ""367 Sulc patent is an oral appliance containing a male member which attaches to the female member. The apparatus and method described by the ""367 Sulc patent, although particularly useful for attaching to a dental surface adjacent to a desired anchoring site, is not optimal for all anchoring requirements.
Another anchoring method and apparatus is described by U.S. Pat. No. 5,749,732, issued to Sendax (xe2x80x9cthe Sendax patentxe2x80x9d or xe2x80x9cSendaxxe2x80x9d). The apparatus described by the Sendax ""patent comprises a threaded anchor post having a square male upper extension. Using a wrench having a square socket, the threaded portion is rotated to attain threaded engagement with a bone. After the threaded portion has penetrated the bone to a suitable depth the square male upper extension remains above the gum. The threaded post portion has a lower threaded portion and an upper threaded portion separated by an unthreaded land. The Sendax patent describes the unthreaded land as functioning to assist bone growth engagement, thereby securing the anchor from unthreading. The square upper extension mates with, and is secured by adhesive to an oral appliance having a corresponding square receptacle.
There are commercially available anchors similar to the device described by Sendax but without the unthreaded land.
The apparatus and method described by the Sendax patent, and the similarly structured commercial products have shortcomings. One is that the upper extension and its cooperative fit with a dental appliance offers little, if any, adjustment after insertion. More particularly, the orientation of the upper extension is fixed by the rotational angle and insertion angle of the threaded portion. The orientation of the receptacle in the dental appliance, which is shaped to correspond to the upper extension, is also fixed relative to the appliance. However, after the threaded portion is screwed into the recipient""s bone, changing its angle requires removal and re-insertion. After a period of time bone growth fixes the rotational position as well. Therefore, after insertion of the threaded anchor the angle and position of the dental appliance is substantially fixed.
Various methods and apparati for adjusting the angle of a dental appliance anchor are known. For example, U.S. Pat. No. 4,713,04, issued to Linkow et. al (xe2x80x9cLinkowxe2x80x9d) discloses an implant placed in the bone and rotated into a proper orientation. Linkow shows a wedge shaped collar having an angled upper surface, which is described as positioned to coincide with the angle of the shaft so that the free end of the shaft extends perpendicularly from the angled surface. Linkow further shows a prosthetic tooth anchor threaded onto the free end of the shaft, to secure the collar in a fixed orientation. The Linkow apparatus and method, although directed to an alignment issue, is relatively complex and may have insufficient structural rigidity for some applications.
While the above-identified and other references describe apparati and methods for aligning prosthetic teeth and other dental appliances, there are various shortcomings. One is complexity of the apparatus. Another includes the difficulty of installation. Other shortcomings include screw access holes on the chewing surfaces of the prosthetic teeth, and limited serviceability of wear components.
An anchor apparatus according to the present invention comprises an implant anchor having a threaded post and an upper circular receptacle, and further comprises a support having a lower circular base having a first longitudinal axis and an upper female prosthesis eyelet, or receptacle, having a second longitudinal axis, the second longitudinal axis and the first longitudinal axis forming a mounting angle with respect to one another, wherein the circular base of the angled support is secured within the upper circular receptacle of the implant anchor.
A further aspect of an anchor apparatus according to the present invention comprises the circular base of the angled support being secured within the upper circular receptacle of the implant anchor by an interference fit and an adhesive.
Another aspect of an anchor apparatus of this invention is in accordance with any of the above-summarized aspects, further comprising a dental prosthesis having a male extension shaped for cooperative engagement with the upper female prosthesis receptacle of the implant anchor, wherein the dental prosthesis is secured to the implant anchor by such cooperative engagement.
The present invention provides a method for anchoring an appliance into an oral cavity having a step of threading an implant anchor having a threaded post into a bone, the implant anchor having an upper circular receptacle, applying an adhesive to an angled support, the angled support having a lower circular base and an upper female prosthesis receptacle, the circular base having a first longitudinal axis and the upper female prosthesis receptacle having a second longitudinal axis, the second longitudinal axis and the first longitudinal axis forming a mounting angle with respect to one another, inserting the circular base of the angles support into the circular receptacle, rotating the circular base about the first longitudinal axis within the circular receptacle until the second longitudinal axis points in a desired direction, and allowing the adhesive to set.
A further aspect of the method of this invention is in accordance with the previously summarized method, further comprising the additional step providing a dental prosthesis having a male extension shaped for cooperative engagement with the upper female prosthesis receptacle of the implant anchor, and attaching the dental prosthesis by such cooperative engagement.
A still further aspect of the method of this invention is in accordance with any of the previously summarized methods, and further comprising the steps of providing a plurality of the angled supports, each of the plurality having a respective mounting angle; providing an alignment apparatus; inserting the alignment apparatus into the female prosthesis receptacle to determine which of the plurality of angled supports achieves a desired position for a dental prosthesis, and using the determined angled support for the steps of applying an adhesive and inserting the circular base of the angles support into the female prosthesis receptacle.
In view of the above-identified and other shortcomings in the prior art, an object of the present invention is a dental appliance anchor having a simple but strong structure that is easy to install.
Another object is a dental appliance anchor that provides ready adjustability in orientation and position.
Another object is a dental appliance anchor in which wear components can be readily replaced without a complete removal of the anchor.
These and other objects, features and advantages of the present invention will become more apparent to, and better understood by, those skilled in the relevant art from the following more detailed description of the preferred embodiments of the invention taken with reference to the accompanying drawings, in which like features are identified by like reference numerals.